[TINKERPOP-1328] Provide [gremlin-python] as an code executor in docs

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.2.0-incubating
• Fix Version/s: 3.2.1
• Component/s: documentation
• Assignee: Daniel Kuppitz
• Reporter: Marko A. Rodriguez
• Created: 07/Jun/16 16:11
• Updated: 16/Jun/16 16:05
• Resolved: 16/Jun/16 15:19

Description

We currently support [gremlin-groovy] and [gremlin-groovy,modern]-style code block annotations. It would be good to also support [gremlin-python] and [gremlin-python,modern]. Likewise, ensure a generalization for the future when gremlin-ruby and gremlin-php are added.

Gremlin-Python source can be evaluated using Groovy and the Jython ScriptEngine. Suppose the following code block:

[gremlin-python,modern]
g.V().out().name

GROOVY

First, assume the following startup code that should be evaluated once and only once into the Gremlin-Groovy script engine.

import javax.script.ScriptEngineManager
import javax.script.SimpleBindings
loader = new URLClassLoader(new File("/Applications/jython-2.7.0/jython.jar").toURI().toURL()) // JYTHON_PATH is better
jython = new ScriptEngineManager(loader).getEngineByName("jython")
jython.eval("import sys");
jython.eval("sys.path.append('/Users/marko/software/tinkerpop/gremlin-variant/src/main/jython/gremlin_python')"); // PYTHON_PATH is better
jython.eval("from gremlin_python import *");

jythonBindings = new SimpleBindings();
jythonBindings.put("g", jython.eval("PythonGraphTraversalSource('g')"));
jython.getContext().setBindings(jythonBindings, javax.script.ScriptContext.GLOBAL_SCOPE);

The above requires that a global variable exist to where Jython is installed as well as to where Gremlin-Python is installed. Though, for the latter, you will simply be able to use pip to install dynamically (PYTHON_PATH) is set to the location of Gremlin-Python.

From there, the code block above would be evaluated as:

g = TinkerGraphFactory.createModern().traversal()
Eval.me("g", g, jython.eval("g.V().out().name").toString())

This looks as follow:

gremlin> g = TinkerFactory.createModern().traversal()
==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]
gremlin> Eval.me("g", g, jython.eval("g.V().out().name").toString())
==>lop
==>vadas
==>josh
==>ripple
==>lop
==>lop

And thats that...

Issue Links

• is related to: TINKERPOP-1278 Implement Gremlin-Python and general purpose language variant test infrastructure